KR940000776B1 - Process for preparing a liquid coffee aroma - Google Patents

Abstract

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Description

Method for preparing liquid coffee flavor

The present invention relates to a process for preparing a liquid aroma containing a concentrated coffee flavor compound from a mill gas frost. Liquid flavors prepared according to the present invention can be used to flavor coffee substrates such as spray dried coffee, freeze dried coffee or roasted and ground coffee, or glycerides such as coffee oil, or other foods.

Powders of soluble beverages, such as spray dried coffee, are relatively fragrant compared to their parent material, ie roasted and ground coffee. Most caffeinated coffee and crushed roasted coffee as described in US Pat. No. 1,903,362 to McKinnis, US Pat. No. 3,615,667 to Joffee and US Pat. No. 4,261,466 to Mahlmann et al. Some types of roasted and ground coffee material are lightly fragrant. These lightly scented beverage powders and products are low in scent from the outset, so the consumer only feels the light scent when opening the container for the first time, and the amount of scent present in the product after the first opening of the container. The drastic shrinkage results in little or no odor when the container is reopened during normal use.

To date, most efforts to add natural flavor to soluble coffee products have focused on adding the flavor of roasted coffee to soluble coffee, such as spray dried or freeze dried coffee. Almost all commercially available soluble coffee is formulated with coffee oil by spraying pure coffee oil or flavor-enhanced coffee oil onto soluble coffee before packaging. In this way, the soluble coffee material has a more aroma than roasted and ground coffee without caffeine removal. The addition of oil is usually known oil plating methods or lupusene, for example as described in US Pat. No. 3,077,405 to Clinton et al. And US Pat. No. 3,148,070 to Mishkin et al. And oil injection methods such as those described in US Pat. No. 3,769,032 to Lubsen et al.

Coffee oil with or without added aroma has been used as a preferred medium for flavoring coffee ingredients, since such products are still pure coffee. However, techniques developed for producing coffee oils, such as solvent extraction of coffee oil from roasted coffee, or squeezing coffee oil, provide manufacturers with cakes left after squeezing roasted coffee or coffee oil containing solvent, both It is not particularly preferable because all must be further processed or removed. The prior art also has several other drawbacks, including the low flowability of coated coffee particles and undesirable oil droplets that may appear on the surface of liquid beverages made from coated coffee. In order to overcome these drawbacks and disadvantages of using coffee oil or other glyceride materials, it is desirable to develop alternative media for flavoring coffee materials.

Each of US Pat. Nos. 2,306,061 and 3,823,241 to Johnston and Patel et al. Provide a coffee mill gas to the beverage material by direct contact with the mill material and the beverage material cooled to at least -15 ° C. The method is described. These documents exclude the use of coffee oil as the medium to impart coffee aroma by allowing the mill gas to be in direct contact with the substance to be flavored. However, this method is not commercially advantageous for several reasons, and the main reasons are as follows. That is, the direct contact of the grinder gas with the substrate is inefficient as a means of mass transfer, and the retention time required for the contact is not only inefficient for continuous coffee processing but also controls the degree to which the aroma is imparted by the method. Because it is impossible to do.

There are many methods in the art of coffee to flavor glycerides with a grinder gas frost, the grinder having frost condensed by contact with a cooled medium. For example, US Pat. No. 4,119,736 to Howland et al. Discloses removal of an aqueous phase from pressurized vessels containing condenser gas condensed at pressures above about 34.42 atm (506.2 psia) and at temperatures above 0 ° C. (32 ° F.), A method of slowly evacuating a pressurized vessel after contacting the dehydrated grinder gas with glycerides is described. Mahlmann, in US Pat. No. 3,979,528, describes a method for flavoring glycerides by contacting the glycerides with a grinder gas frost in a pressurized vessel under various conditions. The conditions announced by Malman are the rapid release of pressure from a pressurized vessel to atmospheric pressure at temperatures below room temperature. However, according to these documents, as is true throughout the coffee industry, significant coffee aroma is lost to the atmosphere by the exhaust rather than being fixed on the food substrate during the flavoring process.

Thus, it is an object of the present invention to develop an efficient way of imparting flavor to a substrate.

Another object of the present invention is to have a flavored substrate having a coffee aroma comparable to freshly roasted and ground coffee in quality.

Another object of the present invention is to increase the yield of flavored substrates per unit volume of coffee mill gas than in the prior art.

According to the present invention, a pulverizer isolating about 90% of carbon dioxide and 100% (or nearly 100%) of carbon dioxide in the pulverizer gas frost, and then concentrating the frost without moisture to obtain a liquid aroma containing the concentrated coffee flavor compound. A method of concentrating gas frost has been developed. The liquid aroma produced by the process of the present invention can be used to give aroma to a substrate, such as roasted and ground coffee, by contacting a liquid flavor with a glyceride such as coffee oil and then contacting the glyceride with a substrate.

The method of the present invention consists of the following steps.

a) condensing the coffee grinder gas to obtain frost.

b) placing the grinder gas frost into a pressurized vessel.

c) supplying heat to the contents of the vessel such that the frost is paralleled at a pressure of at least about 52 atm (750 psig) to form an aqueous phase, a liquid carbon dioxide phase containing most of the coffee aroma and a three phase gaseous carbon dioxide.

d) draining the aqueous phase from the vessel.

e) cooling the second vessel to a temperature below about -62.2 ° C (-80 ° F).

f) evacuating through the conduit into the second vessel from under the surface of the liquid carbon dioxide in the first vessel for a sufficient time until pressure equilibrium is achieved between the two vessels.

g) separating the first vessel from the second vessel.

h) evacuating the second vessel such that its internal pressure is 0 psig.

i) warming the contents of the second vessel in a sealed state from about -17.8 ° C (about 0 ° F) to about -1.1 ° C (about 30 ° F) to sublimate all remaining carbon dioxide into the gas phase.

j) recovering the highly concentrated liquid coffee aroma from a second vessel essentially free of carbon dioxide.

Concentrated coffee aromas (hereinafter referred to as liquid aromas) prepared according to the present invention can be used to aromatize glycerides such as coffee or other food substrates or coffee oils. Using the concentrated liquid aroma, it has been found that coffee aroma yields are higher and higher quality coffee aroma is recovered than in the prior art, which typically uses a dilute mill gas frost to impart a glyceride medium. It has been found that the soluble coffee powder imparted with the aroma of the liquid of the present invention has a highly desirable flavor or roasted and ground flavor by a professional appraiser. In addition, according to the present invention, when the degree of coffee aroma is recovered in the liquid aroma with respect to the content of the coffee aroma contained in the initial grinder gas, the yield of the coffee aroma was high. Finally, according to the invention, an extremely pure scent, essentially free of carbon dioxide, was recovered.

The present invention relates to blending a liquid aroma containing a concentrated and condensed mill gas flavor from a mill gas frost with coffee solids, glycerides or other food ingredients. In particular, although the present invention is described for coffee mill gas containing 80 to 90% by weight of carbon dioxide, other flavors having higher carbon dioxide contents such as coffee percolater exhaust gas and coffee roaster gas may be used. The containing gas can be used as well, and this is also within the scope of the present invention.

The most readily available source of grinder gas can be obtained by sealing or sealing a coffee grinder, such as a commercial grinder. The gas released from the ground coffee can be removed by a pump or rotary blower and, if necessary, additionally inert, preferably moisture-free gas streams to drive the gas out of the coffee and also substantially inert the grinding operation. It can be used to do it in an atmosphere. This process is described in US Pat. No. 2,156,212, which describes a method for collecting the gas released during roasting, which is released during grinding or grinding of freshly roasted coffee beans. The same applies to the gas collection. In the case of using a pump, it is preferable to cool the gas at a stage before the gas is sucked into the pump so that the heat added by the pumping operation does not degrade the fragrance contained in the gas.

The chemical composition of the effluent gas is mostly carbon dioxide, with the characteristic flavor components of water vapor and roasted coffee. The amount of water in the gas can be lowered by roasting under dry conditions and using a low moisture quenching agent or quenching medium. The exit gas is preferably cooled to about 1.7 ° C. (35 ° F.) to about 10 ° C. (50 ° F.) and passed through a first condenser where substantially moisture is removed. Subsequently, a relatively low moisture gas is injected into a second condenser that is cooled with a liquid gas refrigerant, such as a heat exchanger with a jacketed, vertically mounted wall having scratches on its surface.

500 g of mill gas frost was placed in a precooled 1 liter Hoke cylinder and the cylinder was placed in a 70 ° F. water bath. After the equilibrium pressure of 840 psig was reached, the bomb was held for 1 hour. Three phases of gaseous CO ₂ , liquid CO ₂ and liquid H ₂ O were formed in the vessel.

It is useful as an inert gas stream that can also be used in other steps of the soluble coffee making process.

The fragrance-containing gas condenses in frost form during contact with the heat transfer walls of the condenser. A typical mill gas frost is collected at a liquid nitrogen jacket temperature of about -126.1 ° C to -140 ° C (-195 ° F to -220 ° F), containing about 87% carbon dioxide, about 10% water, and about 3% coffee flavor. do. Thus, the frost removed from the condenser wall is very lean in coffee aroma and thus needs to overcome the relatively lack of aroma characteristics of typical soluble beverage powders such as spray dried coffee. The frost may be kept for a short time at low temperature such as liquid nitrogen so as not to deteriorate, but it is preferable to use the frost immediately according to the present invention.

According to the invention, the mill gas frost is placed in a pressurized vessel. Sufficient mill gas frost is added to ensure that no unsaturated carbon dioxide gas phase is present. The vessel contents are then heated with a water jacket or the like from about 21.1 ° C. to about 13.3 ° C. (70 ° F. to 85 ° F.) to sublimate the mill gas frost to form a superspace pressure. At about 75 psig, the solid carbon dioxide turns into a liquid phase. The temperature for this phase change is about -56.7 ° C (-70 ° F). Under these conditions, as well as some organic flavor, the water and traces of glycerides present remain in the solid state. It is desirable to raise the temperature of the vessel contents to about room temperature, where the grinding spreads the gaseous fragrance and equilibrates between the gaseous carbon dioxide phase, the liquid carbon dioxide phase and the water phase. Although the formation of this liquid carbon dioxide phase is essential for the preservation of fragrance, the presence of excess liquid carbon dioxide requires a longer treatment time. Thus, in a preferred embodiment, the amount of liquid carbon dioxide formed is limited to the amount necessary to solubilize the coffee aroma. This amount can be calculated based on the solubility of the coffee aroma in liquid carbon dioxide. After the frost in the vessel has reached the desired temperature and possibly after equilibrium time of up to several hours, the peak pressure is reached.

At this peak pressure the vessel contents will be in three separate phases including the bottom water phase, the liquid carbon dioxide phase, and the gaseous carbon dioxide phase, with the scent being in each phase. After the pressure in the vessel reaches its maximum value, that is, generally between about 750 psig and about 950 psig, the aqueous phase is removed from the vessel. This can be done simply by draining the water through a valve at the bottom of the container. In one embodiment of the present invention, the liquid carbon dioxide phase is absent by increasing the temperature of the pressurized vessel contents above the critical temperature of about 31 ° C. (87.8 ° F.). This ensures complete removal of the water, as it eliminates any possibility of water entering the liquid carbon dioxide phase. However, to prevent undesired deterioration of the coffee aroma, it should be avoided that the temperature exceeds about 32.2 ° C (about 90 ° F). Optionally, the removed aqueous phase can be contacted with glycerides, preferably coffee oil, in a device that allows for efficient liquid-liquid contact to recover the aroma contained therein.

After evacuating the water phase, the pressurized vessel was at a temperature of 23.9 ° C. (about 75 ° F.) to 29.4 ° C. (about 85 ° F.) and a pressure of about 750 psig to about 950 psig for a sufficient time for the gas-liquid phase to equilibrate in the pressure vessel. Keep it. After equilibration is established and possibly held for up to several hours, the pressurized vessel is moved from below the liquid carbon dioxide surface, preferably from the pressurized vessel bottom through the conduit to the second pressurized vessel. The second pressurized vessel is generally precooled to less than about −62.2 ° C. (−80 ° F.), preferably below −78.9 ° C. (−110 ° F.). The preliminary cooling is effected by circulating a cooling medium, for example liquid carbon dioxide or preferably liquid nitrogen, through a pressurized vessel jacket. The transferred liquid carbon dioxide enters the second pressurized vessel through the moving tube.

The second pressurized vessel was evacuated to atmosphere to have a back pressure of typically about 100 psig to about 200 psig when the liquid carbon dioxide phase entered. When the liquid carbon dioxide phase enters the second pressurized vessel, some of the carbon dioxide is vaporized into the gas phase. The latent heat required for the phase change from liquid to gas phase is provided by the remaining liquid carbon dioxide stream containing the coffee aroma, so that the liquid carbon dioxide and aroma freeze into the solid phase. This freezing of liquid carbon dioxide is further facilitated by the cooled wall of the second pressurized vessel. In another embodiment of the present invention, a series or set of milling gas frosts of a ″ first ″ pressurizing vessel are placed and moved from the bottom to a single ″ second ″ pressurizing vessel simultaneously or continuously. In this embodiment, it is particularly important to prevent the formation of the liquid carbon dioxide phase in the second sublimation step, which will be described later in the size of the second vessel.

The rate at which the liquid carbon dioxide phase moves to the second pressurized vessel should be controlled so that the moving tube from the first pressurized vessel to the second pressurized vessel is frozen and flow is not inhibited. The moving tube is typically allowed to enter from the top of the second pressurized vessel and also typically extends to a distance of about 1/4 to 2/3 of the distance to the bottom of the vessel. The nozzle is typically placed at the end of the moving tube, thus spraying the liquid carbon dioxide phase as the moving liquid carbon dioxide phase passes through the nozzle. The diameter of the moving tube is chosen to provide efficient movement on the liquid carbon dioxide.

Once pressure equilibrium is established between the two vessels, the moving tube is closed. The pressure equilibrium is typically between about 100 psig and about 200 psig, depending on the back pressure maintained in the second pressurized vessel. In order to prevent the relatively odorless gaseous carbon dioxide from entering the second pressurized vessel, it is preferable to immediately shut off the moving tube as soon as the equilibrium is achieved. The completion of the movement may be monitored by mounting a site glass on the moving tube in addition to monitoring the rate of change of pressure in one or both of the pressurized vessels. After shutting off the moving tube, it is typical to remove the gaseous carbon dioxide remaining in the first pressurized vessel. The second pressurized container is evacuated to a pressure of 0 psig and then sealed.

The solid frost contained in the second pressurized vessel is then heated, typically from about -17.8 ° C (about 0 ° F) to about -1.1 ° C (30 ° F), to sublimate all the carbon dioxide contained therein and to A _two- phase system consisting of (CO ₂ ) / liquid (fragrance) is formed. If water is present despite having discharged it in the previous step, the water remains frozen in ice at this temperature range. Optionally, after increasing the temperature of the liquid fragrance above 0 ° C. (32 ° F.), water is discharged from the bottom of the second pressurized vessel, and the liquid system is then subjected to about −17.8 ° C. (about 0 ° F.) to about −1.1 ° C. ( Secondary drainage may be done by cooling back to about 30 ° F.) to re-form the two-phase system of gas / liquid. The two-phase system consists of a liquid coffee aroma and gaseous carbon dioxide. The liquid coffee aroma is then collected from the pressurized container and stored in a sealed container under an inert atmosphere or generally below about −28.9 ° C. (−20 ° F.), preferably below about −78.9 ° C. (−110 ° F.). Done. It is desirable to maintain the system in the pressure vessel for about 30 minutes to 2 hours before removing the liquid coffee aroma from the gas / liquid system.

The liquid coffee aroma produced according to the invention is essentially free of carbon dioxide. The liquid coffee aroma is completely free of carbon dioxide, i.e. 0% carbon dioxide. However, small amounts of up to about 1% by weight of carbon dioxide may be present in the liquid scent by interruption during processing and also by other factors. The total yield (wt%) of the liquid odor based on the original mill gas frost was improved over the prior art methods. Of course, the total yield of liquid scent depends somewhat on the concentration of the scent contained in the grinder gas frost. That is, if the coffee aroma is very thin in the grinder gas frost, it is not expected that a high yield of liquid aroma, typically measured in kg (pounds) of recovered liquid aroma per 45.36 kg (100 lb) of grinder gas frost, is not expected. will be. Nevertheless, it is surprising that the present invention produces liquid perfumes substantially free of carbon dioxide and that the yield of liquid perfumes is further improved than by the prior art methods.

Liquid flavours prepared according to the present invention may be prepared from microglycerides, spray dried, lyophilized or agglomerated coffee substrates, roasted and ground coffee, microporous particles such as those described in Hudak, US Pat. No. 4,389,422 or sugar industry. It can be used to flavor other food ingredients that are apparent to the skilled person. For example, flavoring glycerides, such as coffee oil, can be done by liquid-liquid contact in a batch or continuous system. Flavored glycerides, prepared by contact with the liquid flavour, can be used to flavor coffee powders or other food substrates, providing a flavored roasted and ground coffee flavor to the flavored substrate. Was found.

The liquid odor adsorbed on the dry substrate according to the present invention has been found to be stable upon prolonged storage under an inert atmosphere as is usually present in packaged soluble coffee products. The adsorbed liquid flavours have also been found to give the desired upper space scents in containers and jars, typically described by the phrases "favorable" and "roasted and ground".

Example 1

(A) A 68.04 kg (150 lb) mill gas frost was placed in a precooled pressurized vessel and the pressurized vessel was heated to about 21.1 ° C. (70 ° F.). After the equilibrium pressure reached 850 psig, the pressure vessel was maintained for 1 hour. Three phases of gaseous CO ₂ , liquid CO ₂ and liquid H ₂ O containing most of the coffee aroma were formed in the vessel.

The aqueous phase was discharged and the pressurized vessel was connected to a second pressurized vessel precooled to about -78.9 ° C (-110 ° F). The second pressurized vessel was used as a collection vessel of concentrated anhydrous frost when the contents of the first pressurized vessel were moved through a moving tube located at the bottom of the first vessel.

The second pressurized vessel was evacuated to atmosphere while maintaining a back pressure of about 200 psig until pressure equilibrium was achieved between the two vessels, at which time the second pressurized vessel was maintained at a temperature of about −73.3 ° C. (−100 ° F.). Once the pressure equilibrium was made, the moving tube was shut off. The residual contents in the first pressurized container were removed. After the pressure in the second pressure vessel was lowered to 0 psig, the exhaust pipe was closed.

Thus, the second pressurized container contained a solid frost with a high concentration of coffee. The temperature of the second vessel was raised to about -9.4 [deg.] C. (15 [deg.] F.) to convert the solid frost into liquid odor and gaseous carbon dioxide in the upper space. The vessel was held at about -9.4 ° C. (15 ° F.) for 1 hour.

The liquid aroma was then collected from the container and then stored in a sealed container at about -78.9 ° C (-110 ° F). Analysis by gas chromatography proved that the liquid flavor contained no carbon dioxide, and found that the liquid flavor contained a very rich coffee flavor as measured by a total GC count of 3.5 × 10 ⁶ .

Example 2

A control liquid flavor was prepared according to the following process.

500 g of mill gas frost was placed in a precooled 1 liter Hoke cylinder and the cylinder was placed in a approximately 21.1 (70 ° F.) water bath. After the equilibrium pressure of 840 psig was reached, the bomb was held for 1 hour. Three phases of gaseous CO ₂ , liquid CO ₂ and liquid H ₂ O were formed in the vessel.

After the aqueous phase was discharged, one liter Hoke cylinder was connected to a two liter Parr cylinder pre-cooled to approximately −78.9 ° C. (−110 ° F.) and maintained in dry ice. Parr cylinders were used as collection vessels of concentrated anhydrous frost while Hoke cylinders were vented through holes in the bottom.

A 2 liter Parr cylinder was evacuated to atmosphere while maintaining a back pressure of about 80 to 200 psig. When the pressure in the Hoke bomber dropped to 375 psig, each was separated from each other by closing the tube connecting the Hoke cylinder to the Parr cylinder. The gas phase remaining in the Hoke bomb was then removed.

Thus, the Parr bomber contained a coffee-rich solid frost. This solid frost was about 20%, or about 100 g, of the original mill gas frost. The temperature of the Parr bombe was raised to about −17.8 ° C. (0 ° F.) to convert solid frost to liquid. The Parr bomb was kept at about −17.8 ° C. (0 ° F.) for 7 hours, and all gaseous carbon dioxide released from the boiling liquid aroma was maintained as the top space gas in the Parr bomb. The liquid was then collected from Parr Bomb.

The physical and chemical properties of the control liquid odor of this example prepared from the same mill gas frost and the liquid odor of Example 1 are shown in the following table.

By comparing the above data, the efficiency of the liquid flavor production process of the present invention is improved and increased, particularly as evidenced by the increase in coffee flavor yield based on weight. It can be seen that the quality has improved as evidenced by the count, and the purity has improved as evidenced by the complete removal of carbon dioxide.

Claims (14)

(a) condensing the coffee mill gas to obtain a frost; (b) placing the mill gas frost into a pressurized vessel; (c) supplying heat to the contents of the vessel such that the frost equilibrates at a pressure of at least 750 psig to form three phases of the aqueous phase, the liquid carbon dioxide phase and the gaseous carbon dioxide phase: (d) evacuating the aqueous phase from the vessel. ; (e) cooling the second vessel to a temperature below −62.2 ° C. (−80 ° F.); (f) evacuating through the conduit from the bottom of the liquid carbon dioxide surface in the first vessel into the second vessel for a time sufficient to achieve pressure equilibrium between the two vessels; (g) separating the second pressurized vessel from the first vessel; (h) evacuating the second vessel such that the pressure in the vessel reaches 0 psig; (i) warming the contents to a temperature between −17.8 ° C. (0 ° F.) and −1.1 ° C. (30 ° F.) with the second container sealed, thereby vaporizing all remaining carbon dioxide contained therein into the gas phase; ; And (j) recovering the highly concentrated liquid coffee aroma from the second vessel that is substantially free of carbon dioxide. The method of claim 1, wherein the second vessel of step (e) is cooled to below −78.9 ° C. (−110 ° F.). The method of claim 1 wherein evacuating step (f) is performed from the bottom of the first vessel. The method of claim 1 wherein in step (f) the second vessel is evacuated to atmosphere while maintaining a back pressure of 100 psig to 200 psig. The method of claim 1, wherein the second vessel is maintained below −78.9 ° C. (−110 ° F.) through steps (f), (g), and (h). The method of claim 1, wherein the nozzle is attached to the end of the conduit of step (f) in the second container. The process of claim 1 wherein the contents of the second pressurized vessel of step (i) are warmed to 0 ° C. (32 ° F.) to 4.4 ° C. (40 ° F.) to form three phases of an aqueous phase, a liquid carbon dioxide phase and a gaseous carbon dioxide phase. After evacuating the water phase, the vessel further comprises cooling the vessel to -17.8 ° C (0 ° F) to -1.1 ° C (30 ° F). The method of claim 1 wherein the sublimation of step (i) is carried out for 30 minutes to 2 hours. The method of claim 1 further comprising contacting the liquid flavor with a food substrate. The method of claim 9, wherein the substrate is coffee powder. The method of claim 10, wherein the coffee powder is microporous. The method of claim 9, wherein the substrate is glycerides. The method of claim 12, wherein the glyceride is coffee oil. The method of claim 9, wherein the substrate is roasted and ground coffee.